This prototype was a try to quickly get a tank with even more firepower than the T 34/85. The concept was the same as the invention of the T 34/85 but now this very model was the prototype for the new one. A heavy 100 mm gun was put on a hull from a T 34/85 that had a bigger turret, and that was it. Unfortunately the result wasn't quite the same success as model before, and the prototype was not developed further. The heavier guns had to stay on the heavy tanks, especially the new magnificent JS 3 that was developed at about the same time.